This invention relates to a remotely controlled mirror, for example an outside mirror which is located remotely from a driver of a vehicle such that it is impossible for the driver to adjust the inclination angle of the mirror surface, and more particularly to the driving device of such mirror.
The outside mirror of a vehicles is used to provide for the driver the rear and side views and assures safeness when the vehicle is turned to the left or right or outruns another vehicles. For this reason, before driving a motor car the driver adjusts the angle of the outside mirror such that he can see the side and rear views from the drivers seat. However, such outside mirror is located remote from the driver, for example on a fender so that the driver must get off the car and then adjust the mirror by remembering the view which he saw before adjustment after returning to the drivers seat. If the adjustment is not satisfactory he must adjust again.
Since the adjustment of the outside mirror is troublesome, remotely controlled mirrors have been developed recently.
In order to manufacture such remotely controlled mirrors on the mass production basis, the following facts should be taken into consideration. More particularly, the mirror can be readily and accurately adjusted, the construction should be simple and can be manufactured with minimum number of component parts and at low cost, can prevent overload of the operating motor, can readily adjust the inclination angle of the mirror by hand when desired, erroneous operation would not be caused by vibration or shock, and the mirror should be durable. However, various remotaly controlled side mirrors that have been proposed in the past can not fullfill all of these requirements.
For example, the mirror disclosed in Arthur W. Kurz U.S. Pat. No. 3,609,014 dated Sept. 28, 1971 utilizes a three point pivotal connection supporting construction wherein the central pivot connection is fixed so as to permit angular movement of the mirror thereabout, while the other two pivot connection are spaced from the central pivot connections. The latter pivot connections are connected to power means through worm gears and threaded nuts, and constructed such that the mirror can be angularly adjusted about the center pivot by selectively operating the power means.
With this construction, the threaded studs or nuts constituting the latter two pivot connections are pivotally coupled to a supporting plate that supports the mirror but coupled with the worm gears through screw threads so that as the inclination angle of the mirror surface increases a undue force is applied to the thread couplings with the result that the power means for driving the worm gears becomes overloaded thus damaging the same. Such problem limits the angle of inclination of the mirror. This patent also discloses an arrangement wherein the threaded nuts coupled with the threaded studs are replaced by nuts having not threaded bores and a hair pin like spring members are inserted into the slots provided for the nuts to engage the threaded studs. However, since the hair pin like spring is not sufficiently strong it is impossible to transmit large torque to the threaded nuts.
In another example disclosed in Laszlo, N. Repay U.S. Pat. No. 3,978,735 dated Sept. 7, 1976 a single motor is combined with a clutch mechanism. With this construction where it is desired to adjust the inclination angle of the mirror beyond a limit or to manually adjust the inclination angle the driving motor is overloaded and other elements are also subjected to undue forces. Accordingly, for the purpose of avoiding these problems a slip mechanism is interposed between an adjusting screw connected to the back plate of the mirror and worm driven nuts.
However, the slip mechanism utilized in said patent is made up of a number of component element so that its construction is complicated. To provide a slip, a threaded insert having a plurality of teeth is used but with this construction as the number of slips increases the slots of the threaded rod utilized to transmit torque would be damaged. Thus, this construction is not satisfactory from the standpoint of cost and durability.